Abstract

Compared to other lakes, urban lakes are often shallow, highly artificial and hypertrophic due to the higher level of public interface. Bacteria in lake sediment are important participators in the nutrient cyclings in lake ecosystems. In this study, bacterial community compositions in surface sediment of three urban lakes (Lake Xuanwu, Lake Yueya and Lake Pipa) of Nanjing were investigated by using the terminal restriction fragment length polymorphism (T-RFLP) of 16S ribosomal RNA genes followed by cloning and sequencing. At the same time, the response of bacterial community composition to sediment properties was assessed by multivariate analysis. The results indicated that most of the sampling stations in Lake Xuanwu showed similar T-RFLP pattern, suggesting the similar bacterial community compositions in these stations. However, the bacterial T-RFLP patterns varied among different sampling stations in sediments of Lake Yueya and Lake Pipa. Chloroflexi were the most dominant bacterial group in the clone library constructed from Lake Yueya (26.0% of the total clones). WhereasBetaproteobacteria were the most abundant group in the clone library from Lake Pipa (18.6% of the total clones). The higher abundance of Chloroflexi in sediment of Lake Yueya could be attributed to the higher concentrations of organic matters (OM) and total nitrogen (TN) in the sediment. Canonical correspondence analysis (CCA) showed that the bacterial community compositions in lake sediment were significantly related to the concentrations of OM in the sediment, which was associated with the macrophytes and phytoplankton in the lake ecosystems.

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